Killed my paph sanderianum seedling

It was potted into opaque plastic pot with bark. I am not good with bark for anything, just can't say when this stupid thing needs to be watered. It seems that first I rotted some roots and then dried out all the rest.

Now I have a big urge to move St.Swithin and Lady Isabel out of bark and the only thing that stops me - they are in clear pots, so I water when there is no condensation on the pot walls.
Do you have any other hints on how to water paphs in the clear plastic pots with bark. Their roots are always brown, the skewer seems to be always moist